linux-kernel - RE: [PATCH v3] can: m_can: add support for one shot mode

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Message-ID: <01dc01d59467$e6886b20$b3994160$@samsung.com>
Date:   Wed, 6 Nov 2019 11:33:21 +0530
From:   "pankj.sharma" <pankj.sharma@...sung.com>
To:     <wg@...ndegger.com>, <mkl@...gutronix.de>
Cc:     <davem@...emloft.net>, <eugen.hristev@...rochip.com>,
        <ludovic.desroches@...rochip.com>, <pankaj.dubey@...sung.com>,
        <rcsekar@...sung.com>, "'Sriram Dash'" <sriram.dash@...sung.com>,
        <linux-can@...r.kernel.org>, <netdev@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v3] can: m_can: add support for one shot mode

Gentle Ping!

> From: pankj.sharma <pankj.sharma@...sung.com>
> Subject: RE: [PATCH v3] can: m_can: add support for one shot mode
> 
> Gentle Ping!
> 
> > From: Pankaj Sharma <pankj.sharma@...sung.com>
> > Subject: [PATCH v3] can: m_can: add support for one shot mode
> >
> > According to the CAN Specification (see ISO 11898-1:2015, 8.3.4
> > Recovery Management), the M_CAN provides means for automatic
> > retransmission of frames that have lost arbitration or that have been
> > disturbed by errors during transmission. By default automatic retransmission is
> enabled.
> >
> > The Bosch MCAN controller has support for disabling automatic retransmission.
> >
> > To support time-triggered communication as described in ISO
> > 11898-1:2015, chapter 9.2, the automatic retransmission may be disabled via
> CCCR.DAR.
> >
> > CAN_CTRLMODE_ONE_SHOT is used for disabling automatic retransmission.
> >
> > Signed-off-by: Pankaj Sharma <pankj.sharma@...sung.com>
> > Signed-off-by: Sriram Dash <sriram.dash@...sung.com>
> > ---
> >
> > changes in v3:
> > - resolving build errors for net-next branch
> >
> > changes in v2:
> > - rebase to net-next
> >
> >  drivers/net/can/m_can/m_can.c | 12 +++++++++---
> >  1 file changed, 9 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/net/can/m_can/m_can.c
> > b/drivers/net/can/m_can/m_can.c index 562c8317e3aa..75e7490c4299
> > 100644
> > --- a/drivers/net/can/m_can/m_can.c
> > +++ b/drivers/net/can/m_can/m_can.c
> > @@ -123,6 +123,7 @@ enum m_can_reg {
> >  #define CCCR_CME_CANFD_BRS	0x2
> >  #define CCCR_TXP		BIT(14)
> >  #define CCCR_TEST		BIT(7)
> > +#define CCCR_DAR		BIT(6)
> >  #define CCCR_MON		BIT(5)
> >  #define CCCR_CSR		BIT(4)
> >  #define CCCR_CSA		BIT(3)
> > @@ -1135,7 +1136,7 @@ static void m_can_chip_config(struct net_device
> > *dev)
> >  	if (cdev->version == 30) {
> >  	/* Version 3.0.x */
> >
> > -		cccr &= ~(CCCR_TEST | CCCR_MON |
> > +		cccr &= ~(CCCR_TEST | CCCR_MON | CCCR_DAR |
> >  			(CCCR_CMR_MASK << CCCR_CMR_SHIFT) |
> >  			(CCCR_CME_MASK << CCCR_CME_SHIFT));
> >
> > @@ -1145,7 +1146,7 @@ static void m_can_chip_config(struct net_device
> > *dev)
> >  	} else {
> >  	/* Version 3.1.x or 3.2.x */
> >  		cccr &= ~(CCCR_TEST | CCCR_MON | CCCR_BRSE | CCCR_FDOE
> > |
> > -			  CCCR_NISO);
> > +			  CCCR_NISO | CCCR_DAR);
> >
> >  		/* Only 3.2.x has NISO Bit implemented */
> >  		if (cdev->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO) @@ -
> > 1165,6 +1166,10 @@ static void m_can_chip_config(struct net_device *dev)
> >  	if (cdev->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
> >  		cccr |= CCCR_MON;
> >
> > +	/* Disable Auto Retransmission (all versions) */
> > +	if (cdev->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
> > +		cccr |= CCCR_DAR;
> > +
> >  	/* Write config */
> >  	m_can_write(cdev, M_CAN_CCCR, cccr);
> >  	m_can_write(cdev, M_CAN_TEST, test); @@ -1310,7 +1315,8 @@
> static
> > int m_can_dev_setup(struct m_can_classdev
> > *m_can_dev)
> >  	m_can_dev->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
> >  					CAN_CTRLMODE_LISTENONLY |
> >  					CAN_CTRLMODE_BERR_REPORTING |
> > -					CAN_CTRLMODE_FD;
> > +					CAN_CTRLMODE_FD |
> > +					CAN_CTRLMODE_ONE_SHOT;
> >
> >  	/* Set properties depending on M_CAN version */
> >  	switch (m_can_dev->version) {
> > --
> > 2.17.1